In this study, magnetic iron oxide/graphene oxide (Fe 3 O 4 /GO) nanocomposites were developed for removal of cadmium ions (Cd 2+ ) from water, which could be effectively separated from the solution owing to its superparamagnetic property. The Fe 3 O 4 /GO nanocomposites were fabricated by coprecipitation method with different precursor ratios of 8:1, 4:1, 2:1, and 1:1. It was found that the suitable ratio of Fe 3 O 4 /GO for Cd 2+ ions adsorption was 4:1 (FG2). The effects of contact time, pH, and metal initial concentration on the adsorption properties of FG2 for Cd 2+ in water were investigated. The adsorption data of FG2 followed pseudo-second-order kinetic and Langmuir isotherm models with the maximum adsorption capacity of 52.083 mg g −1 at pH 8. The structure and morphology of FG2 were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) specific surface area, and vibrating sample magnetometry (VSM). TEM images of FG2 presented the Fe 3 O 4 nanoparticles in the size range of 10-15 nm decorated on GO nanosheets. The BET specific surface area of FG2 was observed to be 180.84 m 2 g −1 . VSM result of FG2 was 41.13 emu g −1 . Accordingly, FG2 could be considered as a highly efficient adsorbent for removing Cd 2+ from water.

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This study is aimed at studying the adsorption of methylene blue (MB) from aqueous solutions by nickel ferrite/graphene oxide (NGO) nanocomposite. The nanocomposite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, energy dispersive X-ray, Brunauer-Emmett-Teller-specific surface area, and vibrating sample magnetometer analyses. The interactive effects of critical variables including pH, initial concentration, and contact time on the adsorption capacity of NGO for MB were studied using response surface methodology (RSM) according to composite central design. In RSM models, the predicted values agreed well with verification experiments, with a high correlation coefficient of 0.9887. The adsorption process followed the pseudo-second-order kinetic and Langmuir isotherm models. The maximum capacity for adsorption of MB onto NGO was found to be 476.19 mg/g. Based on these results, NGO has the potential as an efficient adsorbent for the removal of MB from water.

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In this work, magnetic graphene oxide nanocomposites were synthesized by co-precipitation method and used as an adsorbent for removal of arsenic (V) ions from water. The structure and morphology of magnetic graphene oxide nanocomposites were studied by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller specific surface area, and vibrating sample magnetometry. Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy results of magnetic graphene oxide presented that the Fe3O4 nanoparticles in the size range of 10–25 nm were decorated on graphene oxide nanosheets. The adsorption properties of magnetic graphene oxide nanocomposites for arsenic (V) from water were investigated to study the effects of magnetic graphene oxide mass ratio, contact time, pH, and initial concentration. The suitable magnetic graphene oxide mass ratio of nanocomposites for arsenic (V) adsorption was determined to be 4:1 (FG2). The adsorption process on FG2 followed a pseudo-second-order kinetic and well fitted in to Langmuir isotherm model with the maximum adsorption capacity of 69.44 mg/g at pH 3. Accordingly, FG2 could be used as an effective adsorbent for removal of arsenic (V) from water.

This work aims to synthesise manganese ferrite/graphene oxide (MnFe2O4/GO) matrrials with various MnFe2O4 contents from 20‐60 wt.% in material for arsenic(V) (As(V)) removal. The nanocomposites were studied by X‐ray diffraction, Fourier‐transform infrared spectroscopy, transmission electron microscopy, Brunauer‐Emmett‐Teller, and vibrating‐sample magnetometry. The suitable mass ratio of MnFe2O4 in nanocomposite for As(V) removal was 50 wt.% (MGO50). The adsorption process on MGO50 followed the pseudo‐second‐order kinetic and Langmuir isotherm models with the maximum adsorption amounts of 212.3 mg/g. Accordingly, MGO50 nanocomposite could be used as an effective adsorbent for removal of As(V) from water.

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